Experimental investigation of mechanical properties of sustainable silica sand reinforced AA6061 composites subjected to thermomechanical treatment

This study investigates the mechanical performance of sustainable AA6061 matrix composites reinforced with silica sand and subjected to thermomechanical treatments. The objective of this study is to assess silica sand as a cost-effective, eco-friendly alternative to traditional ceramic reinforcements in enhancing strength, hardness, and durability. Given the growing demand for sustainable materials in aerospace, automotive, and structural applications, this research explores the potential of silica sand to improve composite properties. The hypothesis is that silica sand, when uniformly dispersed in the AA6061 matrix and processed through rolling and peak ageing, can significantly enhance the mechanical properties. Composites were fabricated via stir casting with 2%, 4%, and 6% silica sand by weight, followed by low-temperature thermomechanical treatment. Mechanical testing included Brinell and Vickers hardness tests, tensile strength evaluation, microstructural analysis, and fracture surface examination. The results revealed consistent improvements with increased reinforcement. Compared to the as-cast composite, the 6% silica sand composite treated at 100 °C with 15% deformation exhibited a 118% increase in hardness and a 62% inrease in tensile strength. Fracture analysis revealed a mixed mode with predominantly brittle failure after treatment. These findings confirm that the combination of silica sand with suitable processing, can produce high-performance, sustainable aluminium composites.